Multi Muff - Project Thread

[kodiakklub]

daryl, would you mind posting your schematic? you kind of are doing something "special" as far as switching caps and all, IMO. thanks.

[daryl]

I'm using a standard GGG schematic and all my mods are off board direct soldered onto rotary switches.

[kodiakklub]

OY. found an error in the schematic in the third stage. new PCB layout finished. hope to have another stab at it in a couple weeks. this thread re-lit the pedal building fire under my arse. thanks daryl!!

[daryl]

Thanks to you too, keeping me going too.

If your really having trouble with popping then another approach is to make sure there is a cap there.

Caps add in parallel, so have the smallest value cap permanently in place, then just add other caps in parallel to get the values you need. Won't work with resistors though as they add in series.
Might be a pain finding the caps but it would work.

[daryl]

I tried the suggestion for the wicker mod in the link, simply removing one leg from each of the three 470pF caps.

It adds more distortion, fizzy distortion.

Sounds good but....

I'm getting some strange noises as the notes decay. (ok for riffing but not good for lead)
It cuts the sustain too with a rough wistling end to the note decay.

Am I doing it right?

[daryl]

Feedback So Far:

The Different values between versions

C6 - C9
This makes a difference 0.047uf Is a smoother distortion and it gets more edgy as the cap values increase.
0.047uF - 0.047uF = Triangle / Russian
0.1uF - 0.1uF = Violet Rams Head / 70's V3
0.1uF - 1.0uF = Rams Head
1.0uF - 1.0uF = Custom
But its in too small incriments to use as above I think I will keep 0.047uF - 0.047uF and 0.1uF - 1.0uF but change the other two values to something with a bigger more noticable difference.
Perhaps:
0.0039uF - 0.0039uF
0.047uF - 0.047uF
0.1uF - 1.0uF
1.47uF - 1.47uF


C2 - C5 - C8
This made practically no difference worth bothering with and is not worth having selectable at all, i'd just leave it as per the schematic
470pF - 470pF - 470pF = Violet Rams Head  / Russian
500pF - 500pF - 500pF = 70's V3
560pF - 560pF - 560pF = Triangle / Rams Head
220pF - 680pF - 680pF = Ram's Head Big Muff "680"

R18 - R19
This seemed to work like this, the bigger the difference between the two resistors the more scooped it got. Also the lower the values got the fuller it sounded. I'm guessing that the lower values cut less lows and highs letting more through.
20k - 22k =  Russian
39k - 39k = Rams Head
39k - 39k = Triangle / Violet Rams Head
39k - 100k = 70's V3

Again though the increments are too small to be useful, I will try changing two of them. Not sure what yet as I havent had time to play with this part perhaps i'll try:
2.2k - 2.2k
20k - 22k
39k - 100k
150k - 250k
See what thats like ang go from there.

Mids Mod
This worked out really well but needs some tweaking on values.
C10 - C11
0.0039uF - 0.01uF =  Scooped Mids  (this is stock values which are ok)
0.0068uF - 0.0068uF = Flat Mids (Dicided to use 0.01uF to save on one CAP and more importantly 2 less wires going to the circuit board as C11 stays at 0.01uF if can be wired  on the board)
0.047uF - 0.0068uF = Mid Hump (0.047 was too much of a difference between C10 and C11, so i'm going to try 0.033uf and 0.022uf instead and picjk the one I like most)



Tone Mod
This was definitely worth doing it gets rid of the mid scoop, slightly less distortion and gives a massive volume boost. To me its too big a volume jump to be used as a boost, but if you add a resistor it changes the amount of volume increase. I'd say that a 170k resistor makes for NO INCREASE as in same sound level. 100k makes for a useable boost. So its basically choose a value between 0 and 100k and you will have a decent boost.


Wicker Mod
i'm not sure If i've done this right I just had a switch lift one side off C2 - C5 - C8. Its useable, adds more fizzy distortion, slight volume increase. But it gets rid of the sustain , with a short decay time. I'm also getting a rough/messy/crackly note decay. Its ok while riffing but sounds bad if you let a single note decay. I think there might be more to the wicker mod than lifting those 3 caps.


Diode Mod
I've not got round to this one yet, as my initial try was not working right.

[diydave]

Keep it up, and thanx for sharing your findings. 
Your project seems to bundle all off the stuff you can find, read and hear about the big muff.

[Jaicen_solo]

Nice work indeed. You should probably make R18 and R19 pots to make it infinitely variable.

I'm going to build a big muff one day, perhaps when you've finished, i'l be standing on your shoulders

[daryl]

Feedback:

Tried
C6-C9
0.0039uF - 0.0039uF
0.047uF - 0.047uF
0.1uF - 1.0uF
1.47uF - 1.47uF

0.0039uF - 0.0039uF = This lets in way too much bass!! So I tried 0.0068 but still too much bass, would be great for bass players though but not great sounding for guitars.
So I'm going to give 0.01uf a go next. I also noticed that the lower you go the volume increases slightly.

Mids Mod
I consider this done now i'm happy with it. C11 stays as 0.01uf on the board now so not switchable
C10
0.0039uF scooped
0.01uF flat
0.033uF hump

[daryl]

Finally got some time to work on the pedal.

Right I've been playing with Diodes.

I'm using this 2P3T,  8 pin,  On-On-On switch.


Because its 8 pins it actually lets me switch both diode sets between 3 options. You can get a toggle that does this but they are expensive over £12 each and rare, but these switches are £0.85 each.

This is how it works:


This is how i've wired it:



I HAVE A QUESTION:

I have found though that wiring it this way the diodes that are switched out of circuit still colour the sound, How can this be when they are not switched into the circuit???

I'm not imagining it either, I checked with several people. I'm not clued up on how diodes work, but if anyone can shed some light on it that would be great. I compared them switched out then clipped out and there is definetly a difference??? Cuts the amount of fizzy fuzz and brightens it a little, I admit it is a subtle difference but still there and I don't like it as much.


QUESTION 2:

Does the way I have the diodes wired work the same as it would on the original circuit board?

I figured both ends of the diodes were joined together by traces so this should work the same?

[EATyourGuitar]

have you tested your switch for off resistance and capacitance? the only thing I can think of is maybe RF or EMI entering through the diode like an antenna. I am a believer after I had a diode on a breadboard today create some oscillation with a practice amp while one side of the diode is in the breadboard but basically floating. strange but true.

[azrael]

Personally, I like diode switching like this:

http://www.muzique.com/news/diode-clipping-switch/

If you need help making a compact PCB, let me know. Layouts are pretty fun to make for me.

[daryl]

Method from the above link:



The problem is I want to bypass the diodes by removing them from the circuit, so leaving the LED's in would not work.

Also the diodes going to ground like that would leave their associated caps out of circuit.

[azrael]

You can do that without them going to ground, and like the same way as the Muff.

If you use diodes with a lower forward voltage than, say in this example, LEDs, nothing passes through the LEDs. Everything gets shunted through the lower voltage threshold pair of cliping diodes. It's science, yo.

[ilcaccillo]

Hi,
just found this thread today while I was looking some info on trying to understand why my DIY Rusian green Muff does't sound like my original unit.

A lot of great info and investigation you've made, congrats for the project and the ideas.

How did your pedal stayed in the end?

Thanks